Synthesis of nanosized ZSM-۵ zeolites by different amounts of sodiumhydroxide and their catalytic performance in methanol to propylene reaction

سال انتشار: 1402
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 125

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شناسه ملی سند علمی:

IICC22_185

تاریخ نمایه سازی: 5 آذر 1402

چکیده مقاله:

Four nanosized ZSM-۵ zeolites were successfully prepared from gels with different Si/Naratios and the same preparation procedures that included the use of tetrapropylammonium bromideas a template and a seeding method. The effect of the amount of sodium in gel on thephysicochemical properties of the prepared samples was investigated by XRD, XRF, N۲physisorption, FESEM, EDX, and NH۳-TPD. The catalytic performance of the nanosized ZSM-۵zeolites in the methanol-to-propylene process was compared. The prepared samples were phasepureand highly crystalline ZSM-۵ zeolites in Na۲O/SiO۲ ratio between ۰.۰۴ to ۰.۱۶۹. The othercomponents in the initial gel were similar. The XRF and EDX results illustrated different Si/Alratios in bulk and surface of synthesized zeolites, respectively. In addition, the change in theamount of sodium hydroxide in the initial gel affected the acidic properties and morphology ofzeolites. The study of the prepared catalysts in methanol to propylene reaction revealed that boththe acid characteristics of the ZSM-۵ and their textural properties such as surface area wereresponsible for their performance in the reaction. A difference in the lifetime of every catalyst wasattributed to the ability of the catalyst to coke forming on acid sites located on the external surfaceof the zeolite crystals. The sample with Na۲O/SiO۲ ratio equal to ۰.۰۸۴ in gel showed moderateacid sites with minimum strength, and this catalyst illustrated maximum surface area. Thepresented results show that the amount of Na۲O used to synthesize ZSM-۵ zeolites is an importantfactor that determines the physicochemical properties, catalytic performance, morphology,selectivity, and acidity of final crystals.

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نویسندگان

Marzieh Hamidzadeh

Catalysis research group, Petrochemical Research & Technology Company, National IranianPetrochemical Company, P.O. Box: ۱۴۹۳, Tehran, Iran.

Solmaz Shifte

Catalysis research group, Petrochemical Research & Technology Company, National IranianPetrochemical Company, P.O. Box: ۱۴۹۳, Tehran, Iran.

Ali Abdolali

Catalysis research group, Petrochemical Research & Technology Company, National IranianPetrochemical Company, P.O. Box: ۱۴۹۳, Tehran, Iran.

Fereydoon Yaripour

Catalysis research group, Petrochemical Research & Technology Company, National IranianPetrochemical Company, P.O. Box: ۱۴۹۳, Tehran, Iran.